Modeling of Polymer Associated Low Salinity Waterflooding by Fractional Flow Theory

According to the positive results of low salinity water (LSW) flooding to recover incremental oil, different studies have been performed to investigate the combination of LSW and other enhanced oil recovery (EOR) methods. Combination of polymer flooding and LSW could be one of the most effective EOR methods. Taking into account the strength and weakness of each individual method, one can take advantage of the synergism between polymer and LSW: presence of polymer improves oil sweep efficiency and LSW decreases polymer adsorption and alters rock wettability to more water-wet. In this paper, we applied fractional flow theory to investigate the performance of polymer-associated low salinity water (LSP) flooding as an EOR method in sandstone reservoirs. Also, application of LSP flooding to recover incremental oil was compared to that of high and low salinity water flooding. The results showed that as LSP was injected into the given sandstone reservoir, there is a delay in water breakthrough time to as much as 0.75 PV. Also, oil recovery duet to the LSP injection increased from 38% to 77% as compared to high salinity water flooding after 1 PV injection. Fractional flow analyses showed that the incremental oil obtained by LSP is mainly due to the presence of two distinct water saturation shock front.